Primary finding
Probable cause
The student pilot’s abrupt control input and the flight instructor’s inadequate remedial action, which resulted in a dynamic rollover.
Investigator assessment
Analysis narrative
The flight instructor was teaching the student pilot to hover the helicopter about 5 ft above a grass area. The student pilot was having difficulty with over-controlling the helicopter and had been applying abrupt control inputs. The flight instructor was demonstrating the behavior of the helicopter with the application of collective control when the student pilot raised the collective control too hard, which resulted in the helicopter tilting right. The flight instructor attempted to correct, but the student pilot was holding the controls tightly and the helicopter’s right skid contacted the ground, resulting in a dynamic rollover. The flight instructor reported that there were no preimpact mechanical malfunctions or failures of the helicopter that would have precluded normal operation.